In the past, radio frequency broadcasts of audio or audio-video programming have used analog technology with a single program per carrier frequency (often referred to as a station or a channel). While there has been some limited capability to offer alternative programming on a single channel such as Secondary Audio Programming (SAP) included in the television broadcast standard in the United States, the advent of digital technology provided the capability to offer multiple, simultaneous programs on a single station. Digital broadcast standards such as those from the Advanced Television Systems Committee (ATSC) for television and the in-band on-channel (IBOC) system developed by iBiquity Digital Corporation for AM and FM radio allow several completely independent, simultaneous programs to be combined into a single broadcast signal and sent out in one channel's frequency allocation.
Users have grown accustomed to the model where there is a one-to-one correspondence between the programming and the carrier frequency. For radio broadcasts, they are required to tune to the actual carrier frequency to hear the station; tuning to 90.3 MHz actually sets the tuner to demodulate the carrier at 90.3 MHz. For television, a channel model is used where an arbitrary number from 2-69 is used to represent a carrier frequency ranging from 55.25 MHz to 801.25 MHz. Once a digital carrier with multiple simultaneous programs is broadcast, as allowed by the ATSC and IBOC standards, the tuning model must be enhanced. While a station frequency or channel number is still required, another parameter to select the desired program, or subchannel, from the plurality of programs included in the signal is also required. In many TV and radio receivers today, this additional subchannel parameter can be directly entered as a suffix to the frequency or channel. Most receivers also insert the added subchannels as virtual channels between the analog channels. For example, if the user hits the “Tune Up” button while listening to a radio station at 90.3 with three subchannels called main program, HD-2 and HD-3, many IBOC compatible radio receivers will tune from the main program at 90.3 to 90.3 HD-2 and then to 90.3 HD-3 before tuning to 90.5. While this provides a way for the user to access the added programming, it does not clearly group all the subchannels of a single station together.
Another common method of tuning a radio is to use preset buttons. Preset buttons allow the user to configure a particular button to always go to a station determined by the user. This mechanism works in the old analog model and has been extended into the digital domain by adding the additional parameter for the subchannel selection to the frequency information that is associated with the button. This invention provides a method of selecting the programming within a single station that can be used in conjunction with these other tuning methods.